Walking Stick Insect

Infestations

In heavy infestations, walking stick insects, both non-native and native, can inflict substantial damage on selected plants, most apparently in neighborhoods, parks, recreational areas and some wilderness areas. Fortunately, most species have no wings. Those have to depend primarily on their spindly legs to expand their range. That slows the spread of damage. Their advance may even be impeded by relatively minor barriers such as streams or roads. By contrast, the mountain pine beetle, which does have wings, has extended its range relatively rapidly, spanning much of the western United States and southwestern Canada, killing tens of millions of acres of pine trees.

Infestations

The walking stick prefers to feed on the foliage of certain broad-leafed plants. It rarely attacks the needle-like leaves of the pines, firs or spruces. Non-native or native, in heavy infestations, it can denude, for example, a stand of oak trees.

Around San Diego, in southern California, for one example, the Indian walking stick (Carausius morosus), an escaped species native to India, has settled in comfortably, "feeding on the lush buffet of plants from ivy to hibiscus," said Elizabeth Fitzsimons, writing for The San Diego Union-Tribune in 2004.

In the eastern half of the United States, the native species called "Diapheromera femorata" has defoliated stands of black oak, basswood and wild cherry, according to Louis F. Wilson, U. S. Department of Agriculture Forest Service, Forest Insect & Disease Leaflet 82.

In the Ouachita National Forest of Arkansas and Oklahoma, heavy Diapheromera femorata infestations have defoliated stands of oaks and other hardwoods, sometimes killing back branches and, in some cases, even trees.

The walking stick leaves a distinctive mark, devouring an entire leaf blade, down to the base of the heavy leaf veins. By contrast, other plant-eating animals - certain grasshoppers or snails, for example - feed on the margins of leaves.

Walking stick near the Texas Gulf Coast. Note the barbed legs.

Control

Should you discover a heavy waking stick infestation in your yard or garden, you may find that control will not be particularly easy. You have several choices, for example:

Invite walking stick predators, for instance, insect-eating birds, to patrol your yard and garden by putting up bird houses. This will take time to be effective.

Hand-pick walking sticks off your plants and boil or burn them, which will kill both the walking sticks and their eggs. This will take patience and persistence to be effective.

Spray plants with a general chemical insecticide for leaf-eating insects. Check with your supplier or an appropriate government agency for recommendations for an insecticide for walking sticks. Read and follow the directions to assure safe and effective use.

Perhaps most importantly, if you keep walking sticks as pets, you should be careful to prevent the escape of either the adults or the nymphs, particularly if the insect is an imported species such as the popular Indian walking stick. The non-native species may become especially destructive because they have none of their natural enemies to control their proliferation.

Common Questions About Walking Sticks

• How do I recognize a walking stick insect?
  
• Can a walking stick cause injury?
• Do walking sticks make good pets?
• How do I control walking stick infestations?